Hello everyone we’re gonna be learning about the world’s first variable compression turbo charged engine which is going to be used in a production vehicle i’m super happy to say that this video is made in partnership with Infiniti who flew me out to the Detroit Auto Show to see the engine in person and talk with infinity engineers to learn all the details about how this engine works. http://technology
and there’s a lot of innovation going on aside from the obvious of changing compression ratio we’ll also chat about the cylinder liner balancing characteristics efficiency characteristics as well as some of the testing to ensure reliability so the initial question is what’s a compression ratio? and why create a car with a variable compression ratio in the first place well the compression ratio. https://worldgraphics20.com/2020/10/27/hacking-the-runway-exploring-5-fashion-technology-haute-tech-couture/
the ratio of the maximum cylinder volume to the minimum cylinder volume can be used to create efficiency and power characteristics of an engine now Infiniti wanted to design an engine that could match the power of a naturally aspirated 6-cylinder engine while still achieving the efficiency and torque characteristics of smaller diesel engines all with improved emissions so how exactly does it work?
well the engine operates on the same basic four strokes as any other engine intake compression power and exhaust that said it can completely alter the compression ratio to target increased horsepower or increased fuel economy there are four basic steps for changing the compression ratio in this engine first a harmonic drive essentially an electric motor rotates an actuator arm second the actuator arm rotates a control shaft similar in principle to a camshaft which forces a lower linkage to move up or down based on the orientation of the cam lobe.
third the lower link changes the angle of the multi-link which is connected by an upper link to the piston finally the upper link moves from the multi links rotation, which causes the piston to move up or down changing the compression ratio so for example if the engine was operating in its power mode but wanted to switch to an efficiency mode the harmonic drive as shown would rotate to the left.
this would then rotate the control shaft which would pull the lower link slightly down this would rotate the multi-link slightly to the right which would then force the upper link slightly upward, decreasing the space between the piston and the cylinder head thus increasing the compression ratio, okay, so now that we understand how it works why would you want to switch between compression ratios?
Starting with the scenario of creating maximum horsepower a low compression ratio of just 8:1 is used this is because the engine is turbocharged so when you pull in significantly more air and fuel with the turbocharger you can make significantly more power however the likelihood of engine knock increases engine knock can be destructive to an engine however by using lower compression ratios.
you can reduce the likelihood of it occurring so when the engine is creating its peak power of 268 horsepower or its peak torque of 287 pound-feet. It’s doing so by lowering the compression ratio and maximizing boost with the turbocharger switching between the two extremes from a compression ratio of 8:1 to 14:1 or vice versa can happen in 1.2 seconds so what about when the engine operates at peak efficiency at a ratio of 14:1?
Well generally speaking the higher a compression ratio used the greater the thermal efficiency of an engine is in other words high compression ratios mean better fuel economy so when the engine is operating at low loads for example when you’re idling or when you’re cruising down the highway it will switch to higher compression ratios to maximize fuel economy now not only does it change the compression ratio.
7 infiniti Reinvents the gasoline engine technology – vc turbo
but it also switches from a traditional engine cycle to the atkinson cycle by altering valve timing the atkinson cycle leaves the intake valve open for a short duration of the compression stroke which means some of the air fuel mixture is pushed out of the cylinder what this does is effectively cause the expansion ratio.
the piston moving down to be greater than the compression ratio the piston moving up which allows the engine to get the maximum amount of useful work out of combustion now so far i’ve made it seem like the engine operates in two distinct modes, but in reality it’s fully variable and can operate it any unique compression ratio between 8:1 and 14:1 ultimately.
the engine will choose the ideal compression ratio for the situation depending on the drivers throttle input if the driver is not asking for power it will adjust the compression ratio to operate as efficiently as possible for the given gas pedal position and the innovation with this engine doesn’t end with a change in compression ratio there are a lot of unique features for example inline 4-cylinder engines are inherently unbalanced that means that the engines vibrate.
and so to compensate four-cylinder engines often use balancing shafts which add complexity and consume power but eliminate the vibration the reason 4-cylinder engines are unbalanced is because of the crankshaft design which creates a secondary force that is not balanced out based on the movement of the piston, you’ll notice however that this engine doesn’t have balancing shafts and that’s because the geometry of the crankshaft assembly does not cause the piston to create a secondary imbalance to my knowledge there’s no other inline 4-cylinder engine out there that won’t have secondary balancing issues without the use of balancing shafts.
so not only can it change compression ratio but it’s beautifully smooth and balanced at any compression ratio it chooses another unique characteristic of this crankshaft linkage is that it nearly? eliminates side forces from the piston on the cylinder walls in a typical engine a piston will have a large opposing side force on the cylinder wall as it also pushes downward rotating the crankshaft.
this is because with normal engines the connecting rod is at a significant angle when rotating the crankshaft this engine however maintains a nearly vertical connecting rod for the combustion stroke as the piston is moving downward which eliminates the side force from combustion against the cylinder wall with less force against the cylinder wall there’s less friction and as the force is all in the desired direction.
This is more efficient now looking at the cylinder liner. You’ll notice. It’s very shiny and reflective this so-called mirror coating is the result of the same plasma sprayed cylinder liner that’s used on the Nissan GTR after the plasma spray is applied there’s a very fine cylinder bore honing which ultimately leaves behind a very strong durable and highly reflective cylinder liner the engine also uses both direct injection and port injection it was found that the most efficient combustion at low loads occurred with both port and direct injection active.
and this also helps to keep the valves clean at higher loads only direct injection is used which meets the power demands and allows for precise fuel injection timing now looking at all of the linkages below the piston it can seem a bit complex and complexity can lead to reliability concerns, so I asked Infinity’s engineers about their testing protocols which were used to develop this engine and what made them confident in the engines reliability.
the testing for this engine as you might imagine was quite extensive the final product is the result of the engine going through over a hundred different prototype iterations from there the engine has been through over three million kilometres of equivalent road testing and 30,000 hours in test beds most impressively 600 development cars were driven around the United States and scattered across the globe testing the engine in every imaginable climate and weather condition.
I asked Infiniti how many cars would be used in testing a more generic? engine design to which they replied about 50, so with 600 test vehicles nearly 12 times the real-world testing was done on this engine to ensure reliability and durability targets were met a few other interesting facts about the engine it has an integrated exhaust manifold so the distance the exhaust travels to the turbo is extremely short helping to spool the turbo quickly.
and also warming up the catalytic converter quickly the total height of the engine is actually the exact same as other four cylinders rather than taller from the added linkage It uses premium octane fuel and it will be first sold in the Infiniti QX50 though it has also debuted in the Q inspiration a concept car highlighting infinities future design language so a huge thank you to Infinity for bringing me out to the Detroit Auto Show giving me an inside look at how this engine works.
mazda,s secret new engine technology
On the last few new car shows we got our hands on somepretty cool new cars. This time, I got to drive a car so new that it’s not even technically made yet. That’s right my babies, daddy drove a prototype. – Aah. Fu– – On the outside, its justa flat black Mazda three. On the inside, livesone of the most advanced combustion engines ever. I want you guys to do me alittle favor really quick, forget everything you knowabout combustion engines.
This one goes: Suck. Squirt. Vortex. Compress. Tons of weird stuff; Squirt again. Lean out. Press. Bang I wanna point out that I didn’t say spark. Today we’re talking about Mazdas, Skyactiv- X. The future of the eternalcombustion engine. Zoom zoom muchachos. (techno music) First things first, this is by far the most expensive car I have every driven, or probably will ever drive. – Aah – It is a ten million dollar car, which they told me afterI drove it around Newport for about three hours.
I could have wrecked this whole thing. It’s literally worth more than Donut. I could have put fifteenpeople out of work. That’s like at least seven kids who aren’t getting Christmas this year. – Haha – Cause Mazda let Uncle Jamesdrive a ten million dollar car and he bottomed it out on a speed bump. (car wheels spinning) The amazing thing about the prototype isn’t how fast it goes.
It isn’t an amazingrumbling from the exhaust, the craziest thing aboutthis ten million dollar car is that it feels normal. Must be nice. Feeling normal. It felt a lot like thecurrent Mazda three, which is exactly what theengineers set out to do. They wanted to make an engine that was super efficient in any revering. You get great mileage, even when you’re ringing it out.
That means you don’t haveto drive like your grandma to get the EPA claimed MPG. You can drive like my grandma. Zoom. Zoom. Mazda is sorta an outlier in the environmentally friendly high MPG, low MPG low emissions game. While most companies are focusing on hybrid and electric technologies, Mazda has decided tomake the most efficient internal combustion engine possible. I mean, what do you expect? These are the same guys who said hey, we should power acar with a magic triangle.
Okay, so how doe thisding-dong thing work? Disclaimer, I’m about touse a lot of words I don’t know the definition of. At times it might seem a little technical or that I might be speaking outside of myrealm of understanding. – A laser. – But pay attention, because I promise it’s very, very interesting. Now you might now that dieselengines are more efficient because it takes lessfuel to make the boom.
The compression is sohigh that it actually ignites the fuel without a spark plug. The thing is, their emissions suck. They shoot a ton of crap out in the air that causes cancer and killsall the trees and stuff. The freaking glaciers all melting and suddenly I got a beach front property. Boom. Boom. Raise the rent. Raise the rent. Mazda set their sightson diesel like efficiency from a much cleanerburning gasoline engine with a thing called High compression combustion ignition, or HCCI.
Basically a gas engine with no spark. Fudge. Until now, this wasimpossible because gasoline is less stable at thesehigher compressions. We couldn’t control whenthe boom was gonna happen. Boom go too soon your engine goes kabloom. (engine combusting) It’s called ping. Pre-ignition. Bad news for baby. The engines the baby. – Haha – HCCI has a limited range of application. Its only dependable when the pistons are moving really quickly.
Because the loadrequirements are much lower. For things like idling oraccelerating from a stop, it doesn’t work. Kabloom. Nigh night baby. Mazda realized they could correct this using a thing calledvariable spark ignition. Think vtech but with spark plugs. Sometimes there’s a spark, sometimes there isn’t. Sometimes there’s a spark, but it doesn’t ignite all the fuel. It just sets off a tiny explosion that pushed the pressure inthe west of the cyllinder past the spontaneous ignition threshold.
Then, all of the rest of the gas ignites because of compression,not because of the spark. Well, because of the spark, but not directly because of the spark. More in like a butterflyeffect sort of way. – Aaah. – When you’re driving, you might accelerate with spark ignition, normal car boom. Then spark control compression ignition and then cruise at thesuper lean sparkless HCCI. So many big words, man I don’t know these words.
So this is basically the gist. I think that most of it is correct. There is like ten millionother things they did to make all this work. Some of it they wouldn’t share with us, some of it I forgot, and the rest of it I didn’t understand. We were listening to the engineers talk for about three hours. I felt like I had to raise my hand to go to the bathroom. Turns out I didn’t. Jesse was superembarrassed and I was like: hey, if you can’t handle me at my worst, you don’t deserve me at my best.
And Jesse’s all: Dude, what are you doing? We’re not boyfriend and boyfriend and you’re yelling in themiddle of this press thing. Anyway, all of the tech that wentinto this weird engine is truly mind boggling. The most impressive thingis that it feels normal. It’s not the fastest thing on the road, not even close. But the fact that it’s so forward thinking and based on the idea ofhaving an efficient car that’s super fun to drive, that’s absolutely exciting.
Yo, thanks for watching the new car show Hit that subscribe button. The more subscribers we get, the more cool stuff we get to do. You wanna learn more about combustion? Watch this episode of Science Garage, where me and Bart blow up some stuff and Bart talks smart things.
how a car work trailer
Do you want to look at a modern car and understand how every single part works? we’re going to fully tear-down this Mazda MX5 Miata and then rebuild the whole car, from scratch, explaining every part as we go. By the time you’re finished watching, you’ll look at this engine and feel like you have a map in your head.
You’ll know what everything is and how it works. This is going to be the most in-depth series on car mechanics ever made. We’re aiming at a minimum of 20 hours content, but honestly, it might be much longer. Because if something is on this car, then we’re going to cover it in detail. We’ll cover the mass air flow meter, the ABS system, and even the simplest little things, like a radiator cap, have some mechanical magic in them.
The thing with cars is that there’s enormous density of engineering, and it can be hard to see clearly what’s happening. Take the front wheel, for example. There’s a whole lot going on here. We’ve got the suspension, the brakes, the steering system and the wheel and tire. Showing things on the car isn’t clear, because there’s too much stuff around to focus on one thing.
If we take parts onto the bench then you can see things better, but now it’s hard to show how this actually relates to the rest of the car. What you need to see is how things work while they’re on the car. So that’s what we’re doing. We’re blowing basically the entire budget on amazing, 3D graphics, that show you exactly what’s going on.
And there’s another massive benefit to investing the time in creating these 3D models. You can explore them yourself on the website and on your phone. We’ll update them as we film the series, and you can try them out today. And we have huge plans for virtual reality. If you’re wondering why I’ve chosen this car, here’s why: it’s a four-cylinder, fuel-injected petrol engine, rear-wheel drive so we can talk about differentials; a manual transmission, which you really need to understand before diving into automatics.
It’s modern, but not cutting edge, which means everything you learn about this car is common to almost every car on the road today. This car is a few years old, so we’ll be handling stuck bolts and rust; real problems that you’ll see on your own car. We’ll discuss all the tools along the way. Using a spring compressor, safely using a jack, using an engine crane, and a huge number of other items.
We’ll show you this amazing machine that cleans parts super fast. And then we’ll show you how you’ll actually clean car parts, sitting on the drive, for ages and ages. And ages. Another way to learn how a car works, is to take it to pieces and scrub every part with your bare hands. Pre-order the video, of course. It’s much easier. The idea behind this course is that if we give you a deep understanding of how a car works, then you’ll be able to fix it, modify it, and do anything that you need to.
And because you understand how things should work, you’ll know precisely what’s going on. Pre-order the course today, and you’ll save a load of money off the normal price. Every cent in pre-orders goes directly into the production budget, which means we can create a course that sets you up for a lifetime of messing around in the garage.